Production of benzaldehyde.



UNITED sTATEs PATENT OFFICE.

JOHN M. WEISS, OF NEW. YORK N. Y., AND

CHARLES R. DOWNS,OF GLIFF SIDE, NEW

JERSEY, ASSIG-NORS TO THE BARRETT COMPANY, A CORPORATION OF NEW JERSEY.

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No Drawing.

To all whom it may concern. I

Be it known that we, JOHN M. Wmssand CHARLES R. Downs, citizens of the United States, residin at 1) 210 West 110th street, New York, and (2? Cliifside, in the counties of (1) -New Yer: and (2) Bergen and States of (1) New York and (2) New Jersey, have lnvented certain new and useful Improvements in the Production of Benzaldehyde, of which the following is a specificaof these or other gases which contain free oxygen, together With a certain amount of blanketing or diluent'gases or steam in order toaid in the control of the rapidity and completeness of the reaction, may bebeneficially employed. It is desirable that the toluol vapors be mixed with a sufiicient amount of the oxygen containing gas to produce the chemical reaction indicated in the equation.

The catalyst may be an oxid of molybdenum such as M00 and may be distributed upon any convenient carriersuch as pumice,

- asbestos, etc. It is preferable to introduce the catalyst or the carrier containing the same into tubes or containers through which the mixture of toluol vapors and oxygen containing gas is passed. The tubes or containers containing the catalyst are heated in any convenient manner until the tempera ture reaches 500 (1., or above, when the desired reaction takes place without the formation of an inordinate amount of byproducts such as H,() and CO thus indicatlng that very little, if any, complete combustion accompanies the reaction.

While the best results have thus far been obtained by using a mixture of air and toluol vapors in'approximately equal proportions,

Specification of Letters Patent.

Application filed June 25-, 1919. Serial No. 806,566.

' above and below ferent proportions of oxygen containing Patented Nov. 1a, 1919.

with an oxid of molybdenum as the catalyst, at a temperature slightly above 500 C.

approximately atmospheric pressure, consldera'bly higher temperatures, say up .to 700 C., or above, may be used at pressures atmospheric and with difgases. It has been found that a very small yleld of benzaldehyde is obtained at temperatures below 500 C. When using a mixture of air and toluol vapors under the above mentioned conditions. Other catalyzers' will produce benzaldehyde mixed with other products, but molybdenum oxid produces only benzaldehyde as a reaction product with water as a by-product.

After the products of reaction have passed out of the reaction zone the condensable portions of the same may be condensed and separated in the usual manner for the recovery of benzaldehyde which may be stored for future use, while the uncondensed gases may be permitted to escape. Any unchanged toluol may be again passed through the reaction zone, such toluene having been enriched with oxygen containing gas, when necessary, before recirculating it through the reaction zone.

Claims:

1. The herein described process which comprises passing a mixture of toluol vapors and an oxygen containing gas through a hot reaction zone which contains an oxid of molybdenum, maintained at a temperature above 500 C., whereby benzaldehyde is produced.

2. The herein described process which comprises passing a mixture of toluol vapors and air through a hot reaction zone which contains an oxid of molybdenum, maintained at a temperature above 500 C. whereby'benzaldehyde is produced.

3. The herein described process which comprises passing a mixture of toluol vapors and an oxygen containing gas through a hot reaction zone which contains an oxid of tures.

- JOHN M. WEISS.

CHARLES R. DOWNS. 

